/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.values;



import com.bff.gaia.unified.sdk.Pipeline;

import com.bff.gaia.unified.sdk.io.WriteFiles;

import com.bff.gaia.unified.sdk.transforms.PTransform;



import java.util.Collections;

import java.util.Map;



/**

 * {@link PDone} is the output of a {@link PTransform} that has a trivial result, such as a {@link

 * WriteFiles}.

 */

public class PDone implements POutput {



  private final Pipeline pipeline;



  private PDone(Pipeline pipeline) {

    this.pipeline = pipeline;

  }



  /** Creates a {@link PDone} in the given {@link Pipeline}. */

  public static PDone in(Pipeline pipeline) {

    return new PDone(pipeline);

  }



  @Override

  public Pipeline getPipeline() {

    return pipeline;

  }



  /** A {@link PDone} contains no {@link PValue PValues}. */

  @Override

  public Map<TupleTag<?>, PValue> expand() {

    return Collections.emptyMap();

  }



  /** Does nothing; there is nothing to finish specifying. */

  @Override

  public void finishSpecifyingOutput(

	  String transformName, PInput input, PTransform<?, ?> transform) {}

}